Field
The present disclosure relates generally to the field of semiconductor device manufacturing and, more particularly, to deposition of silicon nitride based films.
Description of the Related Art
As the physical geometry of semiconductor devices shrinks, deposition processes for forming silicon nitride based films on three-dimensional structures having high aspect ratios is desired. Additionally, it is desirable to be able to deposit silicon nitride based films that demonstrate an advantageous etch selectivity with respect one or more other materials in the formation of a semiconductor device, and/or a desirable etch rate in a dry etch and/or wet etch process.
Deposition of silicon nitride based films having desired characteristics by atomic layer deposition (ALD) processes using reduced thermal budgets can be difficult (e.g., such as at reduced temperatures, including at temperatures of less than about 600° C.). Silicon nitride based films deposited by conventional processes (e.g., silicon nitride based film deposited using plasma enhanced ALD (PEALD)) performed at reduced temperatures may result in films having undesirably low conformality and/or undesirably low film quality inside three-dimensional structures. The low conformality and/or reduced film quality may be due to the anisotropic nature of direct plasmas. Silicon nitride based films formed using conventional methods may also undesirably demonstrate high etch rates and/or have low etch selectivity to another different material in a semiconductor device (e.g., a thermal silicon oxide material, TOX), such that the silicon nitride film cannot withstand one or more subsequent thermal silicon oxide etch steps used in the device fabrication process. For example, the wet etch rate (WER) in dilute aqueous hydrofluoric acid solution (e.g., dHF, or aqueous hydrofluoric acid solution having a concentration of about 0.5 weight %) of a silicon nitride based film deposited using conventional means at temperatures of below about 600° C. typically are too high, for example in comparison to another layer in the film stack (e.g., a TOX layer).